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				<td><h1>CodeIgniter User Guide Version 2.1.3</h1></td>
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		<h1>General Style and Syntax</h1>

		<p>The following page describes the use of coding rules adhered to
			when developing CodeIgniter.</p>


		<h2>Table of Contents</h2>
		<ul class="minitoc">
			<li><a href="#file_format">File Format</a></li>
			<li><a href="#php_closing_tag">PHP Closing Tag</a></li>
			<li><a href="#class_and_method_naming">Class and Method
					Naming</a></li>
			<li><a href="#variable_names">Variable Names</a></li>
			<li><a href="#commenting">Commenting</a></li>
			<li><a href="#constants">Constants</a></li>
			<li><a href="#true_false_and_null">TRUE, FALSE, and NULL</a></li>
			<li><a href="#logical_operators">Logical Operators</a></li>
			<li><a href="#comparing_return_values_and_typecasting">Comparing
					Return Values and Typecasting</a></li>
			<li><a href="#debugging_code">Debugging Code</a></li>
			<li><a href="#whitespace_in_files">Whitespace in Files</a></li>
			<li><a href="#compatibility">Compatibility</a></li>
			<li><a href="#class_and_file_names_using_common_words">Class
					and File Names using Common Words</a></li>
			<li><a href="#database_table_names">Database Table Names</a></li>
			<li><a href="#one_file_per_class">One File per Class</a></li>
			<li><a href="#whitespace">Whitespace</a></li>
			<li><a href="#line_breaks">Line Breaks</a></li>
			<li><a href="#code_indenting">Code Indenting</a></li>
			<li><a href="#bracket_spacing">Bracket and Parenthetic
					Spacing</li>
			<li><a href="#localized_text">Localized Text</a></li>
			<li><a href="#private_methods_and_variables">Private Methods
					and Variables</a></li>
			<li><a href="#php_errors">PHP Errors</a></li>
			<li><a href="#short_open_tags">Short Open Tags</a></li>
			<li><a href="#one_statement_per_line">One Statement Per Line</a></li>
			<li><a href="#strings">Strings</a></li>
			<li><a href="#sql_queries">SQL Queries</a></li>
			<li><a href="#default_function_arguments">Default Function
					Arguments</a></li>
		</ul>

		<li>

			<h2>
				<a name="file_format"></a>File Format
			</h2>
			<div class="guidelineDetails">
				<p>
					Files should be saved with Unicode (UTF-8) encoding. The <abbr
						title="Byte Order Mark">BOM</abbr> should <em>not</em> be used.
					Unlike UTF-16 and UTF-32, there's no byte order to indicate in a
					UTF-8 encoded file, and the <abbr title="Byte Order Mark">BOM</abbr>
					can have a negative side effect in PHP of sending output,
					preventing the application from being able to set its own headers.
					Unix line endings should be used (LF).
				</p>

				<p>Here is how to apply these settings in some of the more
					common text editors. Instructions for your text editor may vary;
					check your text editor's documentation.</p>

				<h5>TextMate</h5>

				<ol>
					<li>Open the Application Preferences</li>
					<li>Click Advanced, and then the "Saving" tab</li>
					<li>In "File Encoding", select "UTF-8 (recommended)"</li>
					<li>In "Line Endings", select "LF (recommended)"</li>
					<li><em>Optional:</em> Check "Use for existing files as well"
						if you wish to modify the line endings of files you open to your
						new preference.</li>
				</ol>

				<h5>BBEdit</h5>

				<ol>
					<li>Open the Application Preferences</li>
					<li>Select "Text Encodings" on the left.</li>
					<li>In "Default text encoding for new documents", select
						"Unicode (UTF-8, no BOM)"</li>
					<li><em>Optional:</em> In "If file's encoding can't be
						guessed, use", select "Unicode (UTF-8, no BOM)"</li>
					<li>Select "Text Files" on the left.</li>
					<li>In "Default line breaks", select "Mac OS X and Unix (LF)"</li>
				</ol>
			</div>

			<h2>
				<a name="php_closing_tag"></a>PHP Closing Tag
			</h2>
			<div class="guidelineDetails">
				<p>
					The PHP closing tag on a PHP document <strong>?&gt;</strong> is
					optional to the PHP parser. However, if used, any whitespace
					following the closing tag, whether introduced by the developer,
					user, or an FTP application, can cause unwanted output, PHP errors,
					or if the latter are suppressed, blank pages. For this reason, all
					PHP files should <strong>OMIT</strong> the closing PHP tag, and
					instead use a comment block to mark the end of file and it's
					location relative to the application root. This allows you to still
					identify a file as being complete and not truncated.
				</p>
				<code>
					<strong>INCORRECT</strong>: &lt;?php echo "Here's my code!"; ?&gt;

					<strong>CORRECT</strong>: &lt;?php echo "Here's my code!"; /* End
					of file myfile.php */ /* Location:
					./system/modules/mymodule/myfile.php */
				</code>
			</div>


			<h2>
				<a name="class_and_method_naming"></a>Class and Method Naming
			</h2>
			<div class="guidelineDetails">
				<p>Class names should always start with an uppercase letter.
					Multiple words should be separated with an underscore, and not
					CamelCased. All other class methods should be entirely lowercased
					and named to clearly indicate their function, preferably including
					a verb. Try to avoid overly long and verbose names.</p>

				<code>
					<strong>INCORRECT</strong>: class superclass class SuperClass <strong>CORRECT</strong>:
					class Super_class
				</code>


				<code>class Super_class { function __construct() { } }</code>

				<p>Examples of improper and proper method naming:</p>

				<code>
					<strong>INCORRECT</strong>: function fileproperties() // not
					descriptive and needs underscore separator function
					fileProperties() // not descriptive and uses CamelCase function
					getfileproperties() // Better! But still missing underscore
					separator function getFileProperties() // uses CamelCase function
					get_the_file_properties_from_the_file() // wordy <strong>CORRECT</strong>:
					function get_file_properties() // descriptive, underscore
					separator, and all lowercase letters
				</code>

			</div>


			<h2>
				<a name="variable_names"></a>Variable Names
			</h2>
			<div class="guidelineDetails">
				<p>The guidelines for variable naming is very similar to that
					used for class methods. Namely, variables should contain only
					lowercase letters, use underscore separators, and be reasonably
					named to indicate their purpose and contents. Very short, non-word
					variables should only be used as iterators in for() loops.</p>
				<code>
					<strong>INCORRECT</strong>: $j = &apos;foo&apos;; // single letter
					variables should only be used in for() loops $Str // contains
					uppercase letters $bufferedText // uses CamelCasing, and could be
					shortened without losing semantic meaning $groupid // multiple
					words, needs underscore separator $name_of_last_city_used // too
					long <strong>CORRECT</strong>: for ($j = 0; $j &lt; 10; $j++) $str
					$buffer $group_id $last_city
				</code>
			</div>


			<h2>
				<a name="commenting"></a>Commenting
			</h2>
			<div class="guidelineDetails">
				<p>In general, code should be commented prolifically. It not
					only helps describe the flow and intent of the code for less
					experienced programmers, but can prove invaluable when returning to
					your own code months down the line. There is not a required format
					for comments, but the following are recommended.</p>

				<p>
					<a
						href="http://manual.phpdoc.org/HTMLSmartyConverter/HandS/phpDocumentor/tutorial_phpDocumentor.howto.pkg.html#basics.docblock">DocBlock</a>
					style comments preceding class and method declarations so they can
					be picked up by IDEs:
				</p>

				<code>/** * Super Class * * @package Package Name *
					@subpackage Subpackage * @category Category * @author Author Name *
					@link http://example.com */ class Super_class {</code>

				<code>/** * Encodes string for use in XML * * @access public
					* @param string * @return string */ function xml_encode($str)</code>

				<p>Use single line comments within code, leaving a blank line
					between large comment blocks and code.</p>

				<code>// break up the string by newlines $parts =
					explode("\n", $str); // A longer comment that needs to give greater
					detail on what is // occurring and why can use multiple single-line
					comments. Try to // keep the width reasonable, around 70 characters
					is the easiest to // read. Don't hesitate to link to permanent
					external resources // that may provide greater detail: // //
					http://example.com/information_about_something/in_particular/

					$parts = $this->foo($parts); </code>
			</div>


			<h2>
				<a name="constants"></a>Constants
			</h2>
			<div class="guidelineDetails">
				<p>
					Constants follow the same guidelines as do variables, except
					constants should always be fully uppercase. <em>Always use
						CodeIgniter constants when appropriate, i.e. SLASH, LD, RD,
						PATH_CACHE, etc.</em>
				</p>
				<code>
					<strong>INCORRECT</strong>: myConstant // missing underscore
					separator and not fully uppercase N // no single-letter constants
					S_C_VER // not descriptive $str = str_replace('{foo}', 'bar',
					$str); // should use LD and RD constants <strong>CORRECT</strong>:
					MY_CONSTANT NEWLINE SUPER_CLASS_VERSION $str =
					str_replace(LD.'foo'.RD, 'bar', $str);
				</code>
			</div>


			<h2>
				<a name="true_false_and_null"></a>TRUE, FALSE, and NULL
			</h2>
			<div class="guidelineDetails">
				<p>
					<strong>TRUE</strong>, <strong>FALSE</strong>, and <strong>NULL</strong>
					keywords should always be fully uppercase.
				</p>
				<code>
					<strong>INCORRECT</strong>: if ($foo == true) $bar = false;
					function foo($bar = null) <strong>CORRECT</strong>: if ($foo ==
					TRUE) $bar = FALSE; function foo($bar = NULL)
				</code>
			</div>



			<h2>
				<a name="logical_operators"></a>Logical Operators
			</h2>
			<div class="guidelineDetails">
				<p>
					Use of <strong>||</strong> is discouraged as its clarity on some
					output devices is low (looking like the number 11 for instance). <strong>&amp;&amp;</strong>
					is preferred over <strong>AND</strong> but either are acceptable,
					and a space should always precede and follow <strong>!</strong>.
				</p>
				<code>
					<strong>INCORRECT</strong>: if ($foo || $bar) if ($foo AND $bar) //
					okay but not recommended for common syntax highlighting
					applications if (!$foo) if (! is_array($foo)) <strong>CORRECT</strong>:
					if ($foo OR $bar) if ($foo && $bar) // recommended if ( ! $foo) if
					( ! is_array($foo))
				</code>
			</div>



			<h2>
				<a name="comparing_return_values_and_typecasting"></a>Comparing
				Return Values and Typecasting
			</h2>
			<div class="guidelineDetails">
				<p>Some PHP functions return FALSE on failure, but may also have
					a valid return value of "" or 0, which would evaluate to FALSE in
					loose comparisons. Be explicit by comparing the variable type when
					using these return values in conditionals to ensure the return
					value is indeed what you expect, and not a value that has an
					equivalent loose-type evaluation.</p>
				<p>
					Use the same stringency in returning and checking your own
					variables. Use <strong>===</strong> and <strong>!==</strong> as
					necessary.

					<code>
						<strong>INCORRECT</strong>: // If 'foo' is at the beginning of the
						string, strpos will return a 0, // resulting in this conditional
						evaluating as TRUE if (strpos($str, 'foo') == FALSE) <strong>CORRECT</strong>:
						if (strpos($str, 'foo') === FALSE)
					</code>

					<code>
						<strong>INCORRECT</strong>: function build_string($str = "") { if
						($str == "") // uh-oh! What if FALSE or the integer 0 is passed as
						an argument? { } } <strong>CORRECT</strong>: function
						build_string($str = "") { if ($str === "") { } }
					</code>
				<p>
					See also information regarding <a
						href="http://us3.php.net/manual/en/language.types.type-juggling.php#language.types.typecasting">typecasting</a>,
					which can be quite useful. Typecasting has a slightly different
					effect which may be desirable. When casting a variable as a string,
					for instance, NULL and boolean FALSE variables become empty
					strings, 0 (and other numbers) become strings of digits, and
					boolean TRUE becomes "1":
				</p>

				<code>$str = (string) $str; // cast $str as a string</code>

			</div>


			<h2>
				<a name="debugging_code"></a>Debugging Code
			</h2>
			<div class="guidelineDetails">
				<p>No debugging code can be left in place for submitted add-ons
					unless it is commented out, i.e. no var_dump(), print_r(), die(),
					and exit() calls that were used while creating the add-on, unless
					they are commented out.</p>

				<code>// print_r($foo);</code>
			</div>



			<h2>
				<a name="whitespace_in_files"></a>Whitespace in Files
			</h2>
			<div class="guidelineDetails">
				<p>No whitespace can precede the opening PHP tag or follow the
					closing PHP tag. Output is buffered, so whitespace in your files
					can cause output to begin before CodeIgniter outputs its content,
					leading to errors and an inability for CodeIgniter to send proper
					headers. In the examples below, select the text with your mouse to
					reveal the incorrect whitespace.</p>

				<p>
					<strong>INCORRECT</strong>:
				</p>
				<code> &lt;?php // ...there is whitespace and a linebreak
					above the opening PHP tag // as well as whitespace after the
					closing PHP tag ?&gt; </code>
				<p>
					<strong>CORRECT</strong>:
				</p>
				<code>&lt;?php // this sample has no whitespace before or
					after the opening and closing PHP tags ?&gt;</code>

			</div>


			<h2>
				<a name="compatibility"></a>Compatibility
			</h2>
			<div class="guidelineDetails">
				<p>Unless specifically mentioned in your add-on's documentation,
					all code must be compatible with PHP version 5.1+. Additionally, do
					not use PHP functions that require non-default libraries to be
					installed unless your code contains an alternative method when the
					function is not available, or you implicitly document that your
					add-on requires said PHP libraries.</p>
			</div>



			<h2>
				<a name="class_and_file_names_using_common_words"></a>Class and File
				Names using Common Words
			</h2>
			<div class="guidelineDetails">
				<p>When your class or filename is a common word, or might quite
					likely be identically named in another PHP script, provide a unique
					prefix to help prevent collision. Always realize that your end
					users may be running other add-ons or third party PHP scripts.
					Choose a prefix that is unique to your identity as a developer or
					company.</p>

				<code>
					<strong>INCORRECT</strong>: class Email pi.email.php class Xml
					ext.xml.php class Import mod.import.php <strong>CORRECT</strong>:
					class Pre_email pi.pre_email.php class Pre_xml ext.pre_xml.php
					class Pre_import mod.pre_import.php
				</code>
			</div>


			<h2>
				<a name="database_table_names"></a>Database Table Names
			</h2>
			<div class="guidelineDetails">
				<p>Any tables that your add-on might use must use the 'exp_'
					prefix, followed by a prefix uniquely identifying you as the
					developer or company, and then a short descriptive table name. You
					do not need to be concerned about the database prefix being used on
					the user's installation, as CodeIgniter's database class will
					automatically convert 'exp_' to what is actually being used.</p>

				<code>
					<strong>INCORRECT</strong>: email_addresses // missing both
					prefixes pre_email_addresses // missing exp_ prefix
					exp_email_addresses // missing unique prefix <strong>CORRECT</strong>:
					exp_pre_email_addresses
				</code>

				<p class="important">
					<strong>NOTE:</strong> Be mindful that MySQL has a limit of 64
					characters for table names. This should not be an issue as table
					names that would exceed this would likely have unreasonable names.
					For instance, the following table name exceeds this limitation by
					one character. Silly, no? <strong>exp_pre_email_addresses_of_registered_users_in_seattle_washington</strong>
			</div>



			<h2>
				<a name="one_file_per_class"></a>One File per Class
			</h2>
			<div class="guidelineDetails">
				<p>
					Use separate files for each class your add-on uses, unless the
					classes are <em>closely related</em>. An example of CodeIgniter
					files that contains multiple classes is the Database class file,
					which contains both the DB class and the DB_Cache class, and the
					Magpie plugin, which contains both the Magpie and Snoopy classes.
				</p>
			</div>



			<h2>
				<a name="whitespace"></a>Whitespace
			</h2>
			<div class="guidelineDetails">
				<p>Use tabs for whitespace in your code, not spaces. This may
					seem like a small thing, but using tabs instead of whitespace
					allows the developer looking at your code to have indentation at
					levels that they prefer and customize in whatever application they
					use. And as a side benefit, it results in (slightly) more compact
					files, storing one tab character versus, say, four space
					characters.</p>
			</div>



			<h2>
				<a name="line_breaks"></a>Line Breaks
			</h2>
			<div class="guidelineDetails">
				<p>Files must be saved with Unix line breaks. This is more of an
					issue for developers who work in Windows, but in any case ensure
					that your text editor is setup to save files with Unix line breaks.</p>
			</div>



			<h2>
				<a name="code_indenting"></a>Code Indenting
			</h2>
			<div class="guidelineDetails">
				<p>Use Allman style indenting. With the exception of Class
					declarations, braces are always placed on a line by themselves, and
					indented at the same level as the control statement that "owns"
					them.</p>

				<code>
					<strong>INCORRECT</strong>: function foo($bar) { // ... } foreach
					($arr as $key => $val) { // ... } if ($foo == $bar) { // ... } else
					{ // ... } for ($i = 0; $i &lt; 10; $i++) { for ($j = 0; $j &lt;
					10; $j++) { // ... } } <strong>CORRECT</strong>: function foo($bar)
					{ // ... } foreach ($arr as $key => $val) { // ... } if ($foo ==
					$bar) { // ... } else { // ... } for ($i = 0; $i &lt; 10; $i++) {
					for ($j = 0; $j &lt; 10; $j++) { // ... } }
				</code>
			</div>


			<h2>
				<a name="bracket_spacing"></a>Bracket and Parenthetic Spacing
			</h2>
			<div class="guidelineDetails">
				<p>In general, parenthesis and brackets should not use any
					additional spaces. The exception is that a space should always
					follow PHP control structures that accept arguments with
					parenthesis (declare, do-while, elseif, for, foreach, if, switch,
					while), to help distinguish them from functions and increase
					readability.</p>

				<code>INCORRECT: $arr[ $foo ] = 'foo'; CORRECT: $arr[$foo] =
					'foo'; // no spaces around array keys INCORRECT: function foo (
					$bar ) { } CORRECT: function foo($bar) // no spaces around
					parenthesis in function declarations { } INCORRECT: foreach(
					$query->result() as $row ) CORRECT: foreach ($query->result() as
					$row) // single space following PHP control structures, but not in
					interior parenthesis </code>
			</div>



			<h2>
				<a name="localized_text"></a>Localized Text
			</h2>
			<div class="guidelineDetails">
				<p>Any text that is output in the control panel should use
					language variables in your lang file to allow localization.</p>

				<code>INCORRECT: return "Invalid Selection"; CORRECT: return
					$this->lang->line('invalid_selection');</code>
			</div>



			<h2>
				<a name="private_methods_and_variables"></a>Private Methods and
				Variables
			</h2>
			<div class="guidelineDetails">
				<p>Methods and variables that are only accessed internally by
					your class, such as utility and helper functions that your public
					methods use for code abstraction, should be prefixed with an
					underscore.</p>

				<code>convert_text() // public method _convert_text() //
					private method</code>
			</div>



			<h2>
				<a name="php_errors"></a>PHP Errors
			</h2>
			<div class="guidelineDetails">
				<p>Code must run error free and not rely on warnings and notices
					to be hidden to meet this requirement. For instance, never access a
					variable that you did not set yourself (such as $_POST array keys)
					without first checking to see that it isset().</p>

				<p>Make sure that while developing your add-on, error reporting
					is enabled for ALL users, and that display_errors is enabled in the
					PHP environment. You can check this setting with:</p>

				<code>if (ini_get('display_errors') == 1) { exit "Enabled"; }</code>

				<p>On some servers where display_errors is disabled, and you do
					not have the ability to change this in the php.ini, you can often
					enable it with:</p>

				<code>ini_set('display_errors', 1);</code>

				<p class="important">
					<strong>NOTE:</strong> Setting the <a
						href="http://us.php.net/manual/en/ref.errorfunc.php#ini.display-errors">display_errors</a>
					setting with ini_set() at runtime is not identical to having it
					enabled in the PHP environment. Namely, it will not have any effect
					if the script has fatal errors
				</p>
			</div>



			<h2>
				<a name="short_open_tags"></a>Short Open Tags
			</h2>
			<div class="guidelineDetails">
				<p>Always use full PHP opening tags, in case a server does not
					have short_open_tag enabled.</p>

				<code>
					<strong>INCORRECT</strong>: &lt;? echo $foo; ?&gt; &lt;?=$foo?&gt;

					<strong>CORRECT</strong>: &lt;?php echo $foo; ?&gt;
				</code>
			</div>



			<h2>
				<a name="one_statement_per_line"></a>One Statement Per Line
			</h2>
			<div class="guidelineDetails">
				<p>Never combine statements on one line.</p>

				<code>
					<strong>INCORRECT</strong>: $foo = 'this'; $bar = 'that'; $bat =
					str_replace($foo, $bar, $bag); <strong>CORRECT</strong>: $foo =
					'this'; $bar = 'that'; $bat = str_replace($foo, $bar, $bag);
				</code>
			</div>



			<h2>
				<a name="strings"></a>Strings
			</h2>
			<div class="guidelineDetails">
				<p>Always use single quoted strings unless you need variables
					parsed, and in cases where you do need variables parsed, use braces
					to prevent greedy token parsing. You may also use double-quoted
					strings if the string contains single quotes, so you do not have to
					use escape characters.</p>

				<code>
					<strong>INCORRECT</strong>: "My String" // no variable parsing, so
					no use for double quotes "My string $foo" // needs braces 'SELECT
					foo FROM bar WHERE baz = \'bag\'' // ugly <strong>CORRECT</strong>:
					'My String' "My string {$foo}" "SELECT foo FROM bar WHERE baz =
					'bag'"
				</code>
			</div>



			<h2>
				<a name="sql_queries"></a>SQL Queries
			</h2>
			<div class="guidelineDetails">
				<p>MySQL keywords are always capitalized: SELECT, INSERT,
					UPDATE, WHERE, AS, JOIN, ON, IN, etc.</p>

				<p>Break up long queries into multiple lines for legibility,
					preferably breaking for each clause.</p>

				<code>
					<strong>INCORRECT</strong>: // keywords are lowercase and query is
					too long for // a single line (... indicates continuation of line)
					$query = $this->db->query("select foo, bar, baz, foofoo, foobar as
					raboof, foobaz from exp_pre_email_addresses ...where foo != 'oof'
					and baz != 'zab' order by foobaz limit 5, 100"); <strong>CORRECT</strong>:
					$query = $this->db->query("SELECT foo, bar, baz, foofoo, foobar AS
					raboof, foobaz FROM exp_pre_email_addresses WHERE foo != 'oof' AND
					baz != 'zab' ORDER BY foobaz LIMIT 5, 100");
				</code>
			</div>



			<h2>
				<a name="default_function_arguments"></a>Default Function Arguments
			</h2>
			<div class="guidelineDetails">
				<p>Whenever appropriate, provide function argument defaults,
					which helps prevent PHP errors with mistaken calls and provides
					common fallback values which can save a few lines of code. Example:</p>

				<code>function foo($bar = '', $baz = FALSE)</code>
			</div>
	</div>



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